Heart failure is a common clinical condition and results in a significant morbidity and mortality. It is defined as the pathophysiologic state in which an abnormality of cardiac function is responsible for the failure of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues or can do so only from an abnormally elevated filling pressure. Heart failure is frequently, but not always caused by a defect in myocardial contraction wherein the strength of contraction of the heart muscle is diminished. In such a case, the term myocardial failure is appropriate. Few therapies exist for myocardial failure that are effective and do not present significant undesirable side effects. The most common treatment of myocardial failure is the administration of cardiac glycosides such as digitalis. While digitalis can alleviate the symptoms and improve cardiac hemodynamics in heart failure, it, as well as the other cardiac glycosides, has a low margin of safety. Such potent drugs cause cardiac dysrythmias and neurological problems as well as nausea, abdominal pain and headache. Further, drug interaction problems are reported with the cardiac glycosides and other common drugs.
What is needed is a method of increasing the strength of the heart contraction without the above described undesirable side effects.